Basic ConceptsBasic ElectronicsDC CircuitsElectric Circuit AnalysisElectrical DesignElectrical Formulas & EquationsElectronics

Diode Formulas & Equations – Zenner, Schockley & Rectifier

Schockley, Zenner & Diode Rectifier Formulas and Equations

Diode Equation for I-V Curve

The I-V curve (diode characteristic curve) can be find by the following no linear equations. This equation is also known as Ideal Equation of Diode or Diode Law.

i = IS ​( eqv/kT – 1 )

Where:

  • i = Current flowing through the diode
  • Is = Reverse or dark saturation current (Typical value for silicon is 10-12 Amperes)
  • e = Base of the neutral logarithm (2.71828)
  • q = Charge on electron (1.602 x 10-19) in coulombs (Absolute Value of electron charge).
  • v = Applied voltage across the diode
  • k = Boltzmann’s constant (1.380 x 10-23 jouals/Kelvin)
  • T = Absolute Temperature in Kelvin (Typical Room Temp is 300 Kelvin)

Diode Formulas & Equations - Zenner, Schockley & Rectifier

Schockley Diode Equation:

Schockley diode equation

Where

  • I= current through the diode
  • V= diode voltage
  • Is = leakage or reverse saturation current
  • n = emission coefficient or ideality factor, for germanium n=1, for silicon it ranges in 1.1-1.8.
  • V= thermal voltage which is

thermal voltage

Where

  • q = charge of electron = 1.6022 x 10-19 coulomb
  • T = absolute temperature in Kelvin (K = 273 + °C)
  • k = Boltzmann’s constant = 1.3806 x 1023 J/K

Zenner Diode Formulas & Equations

You may check the Zener diode based regulator calculator in the previous post.

Series Current

IS = VIN – VZ/RS    …..    (Ohm’s Law)

Zener Current

IZ = IS – IL

Load Current

IL = VL/RL

Load Voltage

VVZ

Change in Load Voltage

∆VL = IZ RZ

Output (Regulated) Voltage

  • VOut = VIN – I R
  • VOut = VIN – (IZ + IL)/RS 
  • VOut = (VIN – IS)/RS

Series Resistance

RS = (V– Vout) / (IZ + IL) = (V– Vout)/(IS)

Max Series Resistance

RS (MAX) = RL (MIN) x [(VIN (MIN) / VZ) -1]

RS (MAX) = RL (MIN) x [(VIN (MIN) – VZ)/IL(MAX)]

Value of Resistor

R = [(VIN (MIN) – VOUT)/(IL + 10)]

Power of Resistor

RP = (VIN (Max) – Vout) 2­­ / R

Power of Zener Diode

ZP = (VIN(MIN) – VOUT) / R) x VOUT

Output Ripple

VR (OUT) ≈ VR (IN) x (RZ/RS)

Diode Rectifier Equations:

A rectifier’s output contains DC as well as AC components, So;

Output DC Power:

Pdc = Vdc Idc­

Where

  • Vdc is the average output voltage
  • Idc­ is the average output current

Output AC Power:

Pac = Vrms Irms

Where

  • Vrms Is the rms of output voltage
  • Irms is the rms of output current

Rectifier Efficiency:

The efficiency of the rectifier denote by η is given by:

Rectifier Efficiency

Where

  • Pdc is the output DC power
  • Pac is the output AC power

Output AC Voltage:

The rms of AC component of the output voltage is:

Output AC voltage Rectifier

Form Factor:

The ratio of RMS voltage to the average dc voltage,

Form Factor

Ripple Factor:

It’s the ratio between the AC and DC component of the rectifier. It shows the purity of the DC output.

Ripple Factor

Related Formulas and Equations Posts:

Show More

Electrical Technology

All about Electrical & Electronics Engineering & Technology. Follow , Twitter , Instagram, Pinterest, YouTube, & Linkedin to get the latest updates or subscribe Here to get latest Engineering Articles in your mailbox.

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top button

Adblock Detected

Our website is made possible by displaying online advertisements to our visitors. Please consider supporting us by disabling your ad blocker. We depends on ad revenue to keep creating quality content for you to learn and enjoy for free.